1. Field of the Invention
The embodiments disclosed relate generally to water drains and more particularly to a fluidic valve water drain for a turbocharger.
2. Description of the Related Art
In reciprocating piston engines, the amount of power is controlled by the amount of fuel burned during the power stroke. For a given cylinder size, the larger the amount of air drawn in during the intake stroke, the larger the amount of fuel that can be mixed in with the intake air or introduced into the cylinder and burned, thus increasing the engine output power. Turbocharger are known devices used to increase the power output of piston engines by compressing air into the engine with a compressor driven by a turbine that harvests energy from the hot engine exhaust gases.
FIG. 1 illustrates a conventional turbocharger 10 having an axial turbine 12 and a radial compressor 14 connected to each other by a mechanical shaft 16. As understood by those of ordinary skill in the applicable arts, in operation, engine exhaust gases (as shown by arrow 18) are guided toward a plurality of blades 20 disposed on a turbine wheel 22 by a turbine inlet housing 24. Expansion of the hot exhaust gases causes the turbine 12 to turn, thus driving the compressor 14 via the mechanical shaft 16. As the compressor 14 turns, an impeller 26 draws air in at the compressor inlet (as shown by arrow 28) and delivers the same to a diffuser 30 disposed inside a compressor housing 32, slowing down the high velocity air, thus converting its kinetic energy to pressure. The pressurized air is then fed into the engine during the intake stroke. The exhaust gases leave the turbine 12 via an exhaust passage 34, after expanding through the blades 20 of the turbine wheel 22. As understood by those of ordinary skill, turbochargers with radial turbines and/or axial compressor may exist and the particular combination illustrated in FIG. 1 is exemplary in nature and in no way limits the scope of the subject matter disclosed herein.
Over time, as turbocharged piston engines operate, some of the additives in the lubricating oil are deposited on the turbocharger turbine nozzle ring and turbine wheel blades 20 (also referred to as buckets). These hard deposits contain calcium sulfate, among other constituents, and, with time, tend to become thicker as engine operation continues. However, despite their hardness, they tend to be readily dissolved in rainwater. Many turbocharged engines, such as those used in a locomotive engine, are designed with a simple stack or relatively open muffler directly above the turbocharger turbine. Thus, if the engine is shut down and no gas is flowing through the turbine, rainwater can accumulate around the stationary turbine parts, as illustrated in FIG. 2 by the water level identified as element 36. If the water level is high enough and the water is undisturbed for a period of time, the deposits on the turbine blades (e.g., see blade 20 in FIG. 2) partially or completely submerged in the water can be locally dissolved, leading to a significant rotor imbalance once the engine is restarted. In many cases this imbalance is sufficient to load the turbocharger bearings to the point of failure soon after a subsequent restart of the engine.
It would therefore be desirable to provide for a mechanism to drain rainwater that may accumulate in the exhaust plenum of a turbocharger with a self-cleaning device with no moving parts in order to minimize maintenance and extend turbocharger useful life.